2 check valves in one assembly to protect the primary water system (city water supply) by providing containment at the water meter Prevents polluted water from entering the potable water supply system by preventing the reverse flow of water into supply lines Cast bronze body and brass union inlet connection Check subassemblies constructed with molded body seats, spring guides and poppets; stainless steel springs, silicone rubber seat discs and Buna-N O-rings